Published 9:47 pm, Friday, October 26, 2012

It's not quite as sexy as Bruce Willis with nukes, but humans could save life on Earth from a killer asteroid using paintballs, according to an MIT student.

Graduate student Sung Wood Paek proposed shooting two clouds of paint-powder pellets at an asteroid from a nearby spacecraft. The first cloud would cover the front of the asteroid, and the second the back.

"The initial force of the pellets would nudge the asteroid off course and the white paint on the surface of the asteroid would more than double its reflectivity, or albedo," according to an MIT video. "An increased albedo would provide additional deflection from enhanced solar radiation pressure."

Paek's paper detailing this strategy won the 2012 Move an Asteroid Technical Paper Competition, sponsored by the United Nations' Space Generation Advisory Council. Paek presented his paper earlier this month at the International Astronautical Congress in Naples, Italy.

Paek's paintball strategy builds on last year's winning idea: Deflecting an asteroid with a cloud of solid pellets.

As a test case, Paek used the asteroid Apophis, a 27-gigaton rock that may come close to Earth in 2029 and again in 2036. He determined it would take five tons of paint to cover the massive asteroid and up to 20 years for the cumulative effect of solar radiation pressure to successfully pull the asteroid off its Earth-bound trajectory.

Another possibility is to fill the balls with aerosols, which would "impart air drag on the incoming asteroid to slow it down," Paek said in an MIT news release. "Or you could just paint the asteroid so you can track it more easily with telescopes on Earth. So there are other uses for this method."

Paek envisions making the paintballs in space, perhaps at the International Space Station, because the violent takeoff of a rocket could cause earth-built pellets to rupture.

"It is very important that we develop and test a few deflection techniques sufficiently so that we know we have a viable 'toolbox' of deflection capabilities to implement when we inevitably discover an asteroid on an impact trajectory," Johnson said in the MIT release.

William Ailor, principal engineer for Aerospace Corp. in El Segundo, Calif., added: "These types of analyses are really timely because this is a problem we'll have basically forever."